Mercedes-Benz
Fuel trim fault, bank 2. On Mercedes V6/V8 most often a dirty or failing MAF sensor.
P0173 fault code: what it means
P0173: Fuel trim fault, bank 2. On Mercedes V6/V8 most often a dirty or failing MAF sensor.
Usual causes, most likely first
- dirty or faulty MAF sensor
- vacuum leak (injector O-rings, brake booster line)
- cracked or loose PCV parts
- fuel supply fault
P0173 by make
What the repair usually costs
- ABS / brake booster actuator replacement (Toyota hybrid)NZ$1,280–NZ$3,430 · A$1,140–A$3,090
- MAF (mass air flow) sensor replaceNZ$170–NZ$660 · A$160–A$600
- Direct-injection petrol injectors (set)NZ$1,490–NZ$3,850 · A$1,350–A$3,520
Not sure what P0173 means on your car? Ask Credov.
Before you clear it
Write the code down or photograph the scanner first. A code that comes straight back after clearing points to a fault that is still there. A car whose codes were cleared just before you arrived may be hiding one: the scanner's readiness monitors show "not ready" for a while after codes are cleared.
Researched by Credov from manufacturer and workshop sources. A fault code points to where a fault may be; a workshop confirms it with a diagnosis. Browse all fault codes.